Quantum Phase Transitions in Capacitively Coupled Two-Dimensional Josephson-Junction Arrays

TL;DR

This paper investigates quantum-phase transitions in capacitively coupled two-dimensional Josephson-junction arrays, revealing an insulator-to-superconductor transition at zero temperature that differs from one-dimensional array behavior.

Contribution

It demonstrates that the transition in 2D arrays cannot be explained solely by particle-hole pairs, highlighting a distinct mechanism from 1D arrays.

Findings

Insulator-to-superconductor transition occurs with increased interlayer capacitance.

Transition mechanism differs from one-dimensional arrays, not solely due to particle-hole pairs.

Zero-temperature quantum-phase transition observed in 2D Josephson-junction arrays.

Abstract

Quantum-phase transitions in two layers of ultrasmall Josephson junctions, coupled capacitively with each other, are investigated. As the interlayer capacitance is increased, the system at zero temperature is found to exhibit an insulator-to-superconductor transition. It is shown that, unlike one-dimensional arrays with a similar coupling configuration, the transition cannot be accounted for exclusively by particle-hole pairs.